A fluid distribution system such as a municipal water system can comprise a hydrant that can permit ready and reliable above-ground access to water by authorized personnel. To turn on water flow through the hydrant, an operating nut positioned on an exterior stem of the hydrant is turned by a wrench to open a water valve inside the hydrant. To discontinue water flowing from the water supply pipe through the hydrant, the operating nut is turned in the opposite direction to close a water valve inside the hydrant.
The operating nut is typically held in place on the stem by a conventional hex nut. Thus, the hex nut and the operating nut can easily be removed by unauthorized users with a conventional wrench or other conventional tools. This can be undesirable in some applications.